The present invention relates generally to rolling cutter drill bits and other drill bits utilizing internal lubricating systems. More particularly, the invention involves a valving system for use in the lubricant passages located internally in such drill bits. In conventional rolling cutter drill bit lubrication systems, such as that disclosed in U.S. Pat. No. 3,923,348 granted to James A. Peck, filed Mar. 13, 1974, for "FRICTION BEARING", which patent is herein incorporated by reference in its entirety, the lubricant passages comprise a grease reservoir chamber connected by internal bore passages to the bearing areas of the bearing journal. Generally, there is no valving in these internal bore passages because of the inaccessibility of the passages and the difficulty of forming additional passages to receive the valving and to provide two-way flow communication. Thus, in the conventional lubricated bits, desirable circulation of lubricant therein is achieved, if at all, only by accident or fortuitously.
The present invention provides valving for conventional lubricant passages in a lubricated drill bit, which valving converts the passages into two-way flow and provides desirable flow paths for the lubricant in the bit.